Fruit peels and cores without the seeds go into freezer bags to make fruit soups, jams, preserves, and jellies with. I will bake apple and pear peels with a little cinnamon and sugar on them to eat just that way.
Lime, Lemon and Orange peels get grated or peeled with my wonderful peeler or they get sliced and candied. Or you can dry the peels in the oven on a very low light..then you have dried orange, lemon or lime peel.
Grapefruit peels get candied and dripped in chocolate, just make sure you take off most of the white pith. You can do the same with Lemon or Orange peels.
Old bread and day old cake without the frosting gets turn into puddings, crumbs, or the cakes get turn into English Trifle. Often I will take the cake that has been frosted and take out the center, crumble it and dry it. Then I can use it as decorting the a cake side with.
Heads, tails, skin and bone for fish or meat gets turn into stock and frozen.
Brown and purple onion tops gets turned into a onion stock. The brown skin gets saved in a paper bag and saved for coloring Easter Eggs. The same is true with the purple onion skins.
Carrot tops are turned into a garnish. Or I plant them and make a lovely fern looking plant as long a little of the carrot is left on them.
Sour milk is used for pancakes, cakes, or bread.
Left over bones from roasts are saved in the freezer then are used to make rich stock. I throw all the bones in one pot. Beef, chicken, pork, and turkey.
Bacon fat is used for rubbing baked potatoes or sauteing in or use to make a roux.
I think of more as time goes on and will add to this list.
Bits of left over meat gets saved in freezer containers to make soups or a quick stew with.
Bits of left over vegtables are saved in freezer containers to make soup or stews with.
A small amount of left over gravy gets used in the next gravy or watered down to use as starter for soups, stews, or instead of add water to a roast.
That Chicken fat on your fresh chicken get pulled off and melted down to baste Chicken with or sautee vegetables in for stuffing.
Left over Turkey fat from the cooked roasted turkey...gets use instead of butter or oil on the next turkey. Or it's used to saute the celery for stuffing.
Small amounts of left Parsley, carrots, onions, celery, are made into a pate' to be use in Minestrone or any vegetable soup.
Celery leaves and stems are frozen to use in soup or stew. I dry the celery leaves in the oven too. Or boil them to make a celery stock for soups or stews.
Raw Potato skins I bake with a little butter and salt. Sometimes I make them cripsy and crumb them using them to top baked potatoes or soups.
Stand by for update..
I save seeds and grow trees and give them as gifts.
Right now I have Chinese apple seeds...never heard of the tree, but the fruit is wonderful. A nurse at the hospital gave them to me. The tree came with her Great Grandfather when he came from China.
When I drain canned fruit I save the juice, syrup or flavored water and use it in jello, instant pudding along with the milk, cakes or breads.
Save your potato water you used to cook your potatoes in...it's great for making beef or pork gravy with. Or you can use it to start your soups or stews with.
If I have enough beef, chicken, turkey leftover, and everyone is tired of hot or cold sandwicks, Tacos and casseroles. I grin the meat to make Piroshki, Kreplach, or Knishes.